The “celing” or maximum attainable altitude of an airplane is limited by the engine output. As the available engine power if reduced by the varified atmosphere at high altitde, it is obvious that a raising of the ceiling by a considrable amount would require either the use of very much larger and heavier engines or some means of supplying the present engines with fule mixture at sea-level pressure. The latter method is the only one worthy of studious considerations an consequently much effort has been expended to develop a supercharger or a supercharging engine that will meet the requirements successfully. In the following article whic was delivered as a paper before the Society of Automotive Engineers, January 7 and 8, 1920, the author reviews the work which has been done and outlines the possibilities of the future—Editor.